Mixing apparatus



Aug. 8, i967 TAKASHI MUKAI MIXING APPARATUS 2 Sheets-Sheet 1 Filed June 28, 1965 INVENTOR.

1967 TAKASHI MUKAI 3,334,869

MIXING APPARATUS Filed June 28, 1965 2 Sheets-Sheet. 2

I N VEN TOR;

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United States Patent 3,334,869 MiXING APPARATUS Takashi Mukai, 553 Mure, Mitaka, Tokyo, Japan Filed June 28, 1965, Ser. No. 467,233 Claims priority, application Japan, Mar. 25, 1965, 40/ 16,897 Claims. (Cl. 259-6) ABSTRACT OF THE DISCLOSURE An upright cylindrical housing is provided with an inlet opening at the upper wall thereof and an outlet opening at the bottom wall thereof. A plurality of preliminary mixing chambers are provided in the housing by partition plates extending horizontally to the longitudinally axis of the housing and parallel to one another in spaced relationship. A homogenizing chamber is formed in the housing below the mixing chambers. Mixing vanes are provided in each preliminary mixing chamber and fitted to a rotatable shaft which rotates at relatively low speed. The preliminary mixing chambers are provided with openings communicating with one another and the final preliminary mixing chamber is provided with an opening communicating with the homogenizing chamber. The homogenizing chamber comprises a rotatable disc rotated by a shaft adapted to rotate at a speed higher than the speed of the first-mentioned shaft, said disc being arranged so that material from the final one of the preliminary mixing chambers falls onto the disc and is flung off under the influence of gravitation force, thereby being subjected to thorough homogenization.

The present invention relates to a mixing apparatus mainly for mixing substances in a powdered or granular form.

Generally known mixing apparatus, a blender mixer or V type mixer for instance, have the advantage that they can bring mixed materials to a degree of about 80% of mixture in a few minutes after the materials are ,charged into a mixer and the mixing operation thereof has begun. However, when a very small quantity of the mixed materials is extracted and examined at that time, it is found to lack homogeneity and requires an additional rather long mixing period before it is found to have undergone the desired uniform rate of mixture.

The present invention is intended to provide an improvement in this situation and accomplishes this aim by providing a mixing apparatus wherein the mixing operation of materials is divided into a pre-mixing step and a homogenizing step, with both steps being performed in succession, and with the homogenizing step being performed almost instantaneously and after the materials have undergone the pre-mixing or preliminary mixing step, whereby an expected uniformly mixed condition of materials is attainable in a short time.

Another object of the present invention is to provide a mixing apparatus which makes the expensive use of premixed materials unnecessary by pre-mixing the materials in the novel apparatus directly and thereupon supplying them to the homogenizing stage, which latter utilizes an "ice upwardly directed disk rotating at high speed. The novel apparatus is also simple and inexpensive to manufacture.

Still another object of the present invention is to provide a mixing apparatus wherein pre-mixing chambers are provided in a vertical series, mixed materials falling downwardly from each preceding to each succeeding one under the influence of stirring vanes provided in each of the pro-mixing chambers, and wherein the thus pre-mixed materials impinge upon a rotary disk and are dispersed in a thin layer from the surface of this disk which is located below the lowest pre-mixing chamber, whereby instantaneous homogenization occurs.

In view of the above described objects and other objects that will be described hereinbelow, an embodiment according to the present invention will be described with reference to accompanyingdrawings in the following.

In the accompanying drawings,

FIG. 1 is a longitudinal sectional view of the mixing apparatus according to the present invention;

FIG. 2 is a sectional view on the line II-II of FIG. 1;

FIG. 3 and 4 are sectional views on the lines III-Ill and IVIV of FIG. 1, respectively, and FIG. 5 is a plan view of the upwardly directed rotary disk of said apparatus.

Describing the embodiment with reference to the accompanying drawings, numeral 1 indicates a cylindrical casing, 2 and 3 the internal and external coaxial shafts which extend through the central axis of said casing 1 and rotate in the same or in mutually opposite direction. Numeral 4 indicates a hopper at the top of the casing and adapted to have desired materials to be mixed charged therethrough. Numeral 5, 5' indicate the pre-mixing chambers formed by partition plates 6, 6' arranged in descending order from the upper to the lower portion of the casing 1, and in the embodiment illustrated in the drawing the pre-mixing step is accomplished in two stages respectively utilizing a first chamber 5 and a second chamber 5', although the number can be greater or smaller.

In the first chamber 5, on the exterior rotary shaft 3 thereof, stirring vanes 8 having bent front end portions 7 for the purpose of moving the materials in mixture outwardly to better the mixing operation are arranged in radially extending relationship above the upper surface of said partition plate 6, and if necessary the stirring vanes 8 may be provided with projections and recesses in form of teeth on the surfaces thereof, whereby the mixing action may be enhanced.

On the partition plate 6 separating the first chamber 5 and the second chamber 5', discharge openings 9 are provided in the peripheral portion thereof in angularly spaced arrangement, and baffie plates 10 for facilitating mixing are provided opposed to said discharge openings 9 on the inner side of the wall of casing 1 so as to cause mixing and falling of the materials in mixture. Further, freely adjustable shutters 11 are additionally provided on said discharge openings 9 in order to prevent the materials in mixture from falling therethrough while being pre-mixed.

Now, describing the sec-0nd chamber 5', stirring vanes 12 similar to that of the first chamber 5 and enabling movement of the materials inwardly, are inwardly curved to be effective for the materials, are provided on the external rotary shaft 3 adjacent to the partition plate 6 J and so constructed that the materials in mixture falling through said discharge openings 9 are moved inwardly and simultaneously mixed. Thereupon, these materials are then supplied to the homogenizing chamber 14 through discharge opening 13 at the central portion of the partition plate 6. Y

The homogenizing chamber 14 is formed by a funnelshaped body 17 secured to the casing 1 and having a lower open end facing substantially the central portion of an upwardly directed rotary disc 16 secured to the internal rotary shaft 2, and a support member 18 supporting the internal and external rotary shafts 2, 3 is secured to the inlet opening 15. An upwardly diverging dispersion surface 16 with an upwardly directed rotary disc 19 in the middle is provided, and shock dispersion pins 20 projecting upwardly with spacing from one another are secured on the periphery of the disc, and stationary shock pins 21 projecting downwardly and arranged in parallel opposed to said dispersion pins 20 are spacedly provided on the lower surface of the bottom wall of the casing 1.

If it is necessary to add a liquid to the materials being mixed, this can be done via annular liquid nozzles 22 provided at the lower periphery of the inlet opening 15.

Numeral 23 indicates a discharge opening for the homogenized materials in the lower portion of the casing, 24 is a bearing mechanism assisting the rotation of the internal and external rotary shafts 2, 3, and 25 and 26 are pulleys for the rotation of the internal and external rotary shafts 2, 3, respectively.

Describing the operation of the apparatus according to the present invention based on the structure described above, two or more different unmixed materials are first introduced into the first chamber within the casing 1 through the hopper 4 and then pre-mixed therein for a certain Period with the shutters 11 closed.

Next, when the mixed condition has reached 60%- 70%, the shutters 11 are opened and the materials mixed by the rotation of the stirring vanes 7 of the first chamber 5, fall into the second chamber 5', and the mixing action is continued therein by the stirring vanes 12 of the second chamber 5', whereby the pre-mixing of the materials is facilitated.

The materials in mixture on completing the pre-mixing operation in the first chamber 5 and the second chamber 5' show only a degree of about 80% mixed condition, and when a very small quantity of the materials in mixture is extracted and examined, it shows that they are not in the state of complete mixture. Now, the materials are permitted to enter into the homogeneity chamber 14 from the second chamber and toward the central portion of the upwardly directed rotary disk 16 through the inlet 15 provided on the opening portion. On impact on the disk the materials are imparted a radial component of movement by the high speed rotation of the disk and expanded to a thin layer by the action of centrifugal force, such layer having substantially one granular form on moving across the dispersion surface 19 from where they are dispersed outwardly.

The shock dispersion pins 20 on the outer periphery of the upwardly directed rotary disk 16 and also the stationary shock pins 21 on the casing 1 are in the path of the material so that the thin layer thereof collides with the group of said pins whereby its advance is checked, resulting in a forced instant mixing action and thereby in the homogenization of the materials.

According to the present invention the steps of premixing and homogenizing are performed in succession, so that the duration of mixture is reduced a great deal, and in addition the apparatus itself is comparatively compact by the combination of the two steps, so that consequently the apparatus, being able to be made at a low cost Without requiring a high cost mechanism, has several advantageous characteristics including the fact that 4 the structural elements of the apparatus are much simplified.

As described above, an embodiment according to the present invention has been described, but the present invention, not being restricted to the embodiment described above, can be applied to mixing apparatuses within the scope of the present invention.

What is claimed is:

1. A multi-stage mixing apparatus comprising, in combination, at least one preliminary mixing chamber and a homogenizing chamber arranged downstream thereof; first and second agitating means operatively associated with said preliminary mixing chamber and said homogenizing chamber, respectively; first and second drive means operatively connected with said first and second agitating means for driving the former at a first speed and the latter at a higher second speed; inlet means communicating with said preliminary mixing chamber for continuously admitting materials to be admixed thereinto, and outlet means communicating with said homogenizing chamber for continuously withdrawing homogenized materials therefrom; and passage means connecting said chambers with one another and arranged to admit partially admixed materials from said preliminary mixing chamber in unidirectional flow into said homogenizing chamber.

2. A multi-stage mixing apparatus as defined in claim 1, wherein said preliminary mixing chamber is arranged upwardly of said homogenizing chamber.

3. A multi-stage mixing apparatus as defined in claim 1, wherein said first agitating means comprise a set of vanes arranged for rotation within said preliminary mixing chamber.

4. A multi-stage mixing apparatus as defined in claim 3, wherein said set of vanes rotates about a predetermined axis, and wherein the vanes of Said set extend substantially radially of said axis.

5. A multi-stage mixing apparatus as defined in claim 4, wherein said vanes each have a free end portions of at least some of said vanes extend tangentially of said axis.

6. A multi-stage mixing apparatus as defined in claim 1; further comprising an additional preliminary mixing chamber interposed between said first-mentioned preliminary mixing chamber and said homogenizing chamber, and wherein said first drive means comprises a first agitating arrangement operatively associated with said preliminary mixing chamber and a second agitating arrangement operatively associated with said additional preliminary mixing chamber, and wherein said passage means connects said first-mentioned preliminary mixing chamber with said additional mixing chamber and the latter with said homogenizing chamber.

7. A multi-stage mixing apparatus as defined in claim 1, wherein said homogenizing chamber is arranged below haid preliminary mixing chamber, and wherein said second agitating means comprises a substantially discshaped rotary member having a surface facing said passage means connecting said prelimiary mixing chamber with said homogenizing chamber.

8. A multi-stage mixing apparatus as defined in claim 7, wherein said surface comprises a first surface portion arranged below said passage means and conically diverging in direction toward the same, and a second surface portion surrounding and radially extending from said first surface portion.

9. A multi-stage mixing apparatus as defined in claim 8; further comprising a stationary second surface above and substantially parallel to said second surface portion of said disc-shaped rotary member, and a plurality of pin members respectively provided on said second surface portion and on said second surface and extending toward one another, said pin members being arranged so as not to interfere with rotation of said disc-shaped member.

10. A multi-stage mixing apparatus comprising, in combination, an upright cylindrical housing having an inlet at the upper end thereof and an outlet at the lower end thereof; means defining Within said housing at least two vertically superposed preliminary mixing chambers and a homogenizing chamber arranged downwardly thereof; passage means connecting successive ones of said chambers; rotary agitator vanes arranged in each of said preliminary chambers for rotaiton about a longitudinal axis of the respective chamber; a rotary agitator disc arranged in said homogenizing chamber downwardly spaced from said passage means and having a surface facing the latter; and drive means for rotating said vanes at a first speed and said disc at a higher second speed.

References Cited UNITED STATES PATENTS Miles 259-67 X Hollstein 25966 X Wedge 259-66 X Willard 259-6 X Teale 259-8 Miller 2598 X Man 2598 McIlvaine 25943 X WALTER A. SCHEEL, Primary Examiner.

I. M. BELL, Assistant Examiner. 

1. A MULTI-STAGE MIXING APPARATUS COMPRISING, IN COMBINATION, AT LEAST ONE PRELIMINARY MIXING CHAMBER AND A HOMOGENIZING CHAMBER ARRANGED DOWNSTREAM THEREOF; FIRST AND SECOND AGITATING MEANS OPERATIVELY ASSOCIATED WITH SAID PRELIMINARY MIXING CHAMBER AND SAID HOMOGENIZING CHAMBER, RESPECTIVELY; FIRST AND SECOND DRIVE MEANS OPERATIVELY CONNECTED WITH SAID FIRST AND SECOND AGITATING MEANS FOR DRIVING THE FORMER AT A FIRST SPEED AND THE LATTER AT A HIGHER SECOND SPEED; INLET MEANS COMMUNICATING WITH SAID PRELIMARY MIXING CHAMBER FOR CONTINUOUSLY ADMITTING MATERIALS TO BE ADMIXED THEREINTO, AND OUTLET MEANS COMMUNICATING WITH SAID HOMOGENIZING CHAMBER FOR CONTINUOUSLY WITHDRAWING HOMOGENIZED MATERIALS THEREFROM; AND PASSAGE MEANS CONNECTING SAID CHAMBERS WITH ONE ANOTHER AND ARRANGED TO ADMIT PARTIALLY ADMIXED MATERIALS FROM SAID PRELIMINARY MIXING CHAMBER IN UNIDIRECTIONAL FLOW INTO SAID HOMOGENIZING CHAMBER. 